1. Field of the Invention
The present invention relates to a construction of an on-vehicle lever switch for providing operational instructions, for example, for turning a headlamp of a vehicle ON and OFF.
2. Description of the Related Art
As a construction of an on-vehicle lever switch in the related art, there is the one disclosed for example in JP-A-10-12100. The construction of the on-vehicle lever switch includes a control lever attached on a steering column for providing electrical operational instructions, for example, for turning the headlamp of the vehicle ON and OFF, and the control lever includes control knobs as rotary knobs disposed on the distal side thereof with a knob middle as a fixed knob interposed therebetween.
The aforementioned knob middle is formed with detent troughs on both axial end surfaces thereof, and a detent ball supported on each control knob is in resilient contact with each detent trough by an urging force of a detent spring. A projection formed on the control knob engages a hole on the knob middle to construct a stopper to limit the rotary movement of the control knob.
Lighting operation such as turning the headlamp ON and OFF is performed by operating such control knobs. During such rotary operation, the detent ball on each control knob is brought into resilient contact with the detent trough on the knob middle to provide detention to the control knob. The limit of rotary movement of the control knob may be determined by abutment of the projection on the control knob against the end of the hole on the knob middle in the rotational direction.
However, in the construction described above, when the control knob is rotated strongly to the limit of movement, the other control knob that is not operated may slightly rotate in conjunction with the rotation of the operated control knob. In other words, when one of the control knobs is rotated strongly to the limit of movement, the projection thereof abuts against the end of the hole on the knob middle, and thus the fixed knob middle is displaced in the direction of rotation due to axial deflection of resin. As a consequent, a rotational force is transmitted via the detent ball in resilient contact with the detent trough of the knob middle and the detent spring to the other control knob that is not operated, and thus the control knob that is not operated may rotate together in the direction of rotation.
Generally, since such coupled rotation of the control knobs may result in malfunction of switches, shank or the like is thickened to increase rigidity of the fixed side so as to prevent rotational displacement of the fixed knob middle from occurring when one of the control knobs is operated.
However, there is a problem that taking such countermeasure as to increase rigidity of the fixed side results in thickening and hence upsizing of the entire lever switch.
Accordingly, it is an object of the present invention to provide a construction of on-vehicle lever switch that may prevent coupled movement of the knobs without upsizing the lever switch.
A first aspect of the invention is a lever switch including a first rotary knob and a second rotary knob disposed on the distal side of a control lever and being capable of providing predetermined electrical operational instructions by rotating the first rotary knob and the second rotary knob about the axis respectively, wherein a first detent mechanism is provided for providing detention against rotational operation of one of the first and second rotary knobs on the distal side of the control lever, a lever guide formed with a lever guide hole is provided on the control lever, a lever shaft extending from the distal side to the proximal side of the control lever is disposed in the lever guide hole, the other one of the first and second rotary knobs is connected to the distal side of the lever shaft, a control rod is provided for providing the electrical operational instructions on the proximal side of the lever shaft, and a second detent mechanism for providing detention against the rotational operation of the other one of the first and second rotary knobs is provided between the proximal side of the lever guide and the control rod.
A second aspect of the invention is a construction of an on-vehicle lever switch as set forth in the first aspect of the invention, wherein the second detent mechanism includes a detent body and a detent spring supported on the control lever and a detent groove formed on the control rod, the control rod includes an engaging section for enabling the electrical operational instructions and a notched section for enabling insertion of the lever shaft along the axial center of the lever guide hole in addition to the detent groove, and a locking section with which the notched side of the control rod engages by an urging force of the detent spring exerted by rotating the control rod in one direction about the axis is provided on the proximal side of the lever guide.
A third aspect of the invention is a construction of an on-vehicle lever switch as set forth in the first aspect or the second aspect of the invention, wherein a stopper for determining the limit of rotation of the control rod by allowing the notched side of the control rod to be abutted when the control rod is rotated is provided on the proximal side of the lever guide.
A fourth aspect of the invention is a construction of an on-vehicle lever switch as stated any one of the second aspect and the third aspect of the invention, wherein a mounting space being in communication with the lever guide hole for arranging the control rod is provided on the proximal side of the lever guide, and a locking hole with which the notched side of the control rod engages to form the locking section and having the stopper is formed on one side of the mounting space intersecting the axial center of the lever guide hole.
A fifth aspect of the invention is a construction of on-vehicle lever switch as set forth in any one of the first aspect to the fourth aspect of the invention, wherein the first rotary knob and the second rotary knob are disposed on the distal side of the control lever with the immovable fixed body interposed therebetween, and the first detent mechanism includes the detent body and the detent spring provided on one of the first and second rotary knobs or on the fixed body, and the detent groove formed on the other one of the first and second rotary knobs with which the detent body is brought into resilient contact by an urging force of the detent spring.
In the first aspect of the invention, the first rotary knob and the second rotary knob are disposed on the distal side of the control lever, and prescribed electrical operational instructions, for example, for turning the headlamp ON and OFF, and turning the fog lamp ON and OFF may be provided by rotating the first rotary knob and the second rotary knob about the axis. When rotating one of the first and second rotary knobs, detention against the rotational operation may be provided by the first detent mechanism.
In the rotational operation of the other one of the first and second rotary knobs, the control rod on the distal side is operated via the lever shaft extending in the lever guide hole from the distal side to the proximal side of the control lever, and a movable element provided with a movable contact point is moved in conjunction therewith, so that the electrical operational instructions, for example, for turning the headlamp ON and OFF may be provided. When rotating the other one of the first and second rotary knobs, detention may be provided by the second detent mechanism provided between the proximal side of the lever guide and the control rod.
As is described above, since the first detent mechanism for providing detention against the rotational operation of one of the first and second rotary knobs is provided on the distal side of the control lever, and the second detent mechanism for providing detention against the rotational operation of the other one of those is provided on the proximal side of the control lever, the first and second detent mechanisms may be prevented from working with each other in the direction of rotation, and thus coupled rotation such that rotation of one of the first and second rotary knobs to the limit causes rotation of the other one of those may be prevented. Therefore, malfunction of one of the first and second rotary knobs caused by the operation of the other one of those may be prevented while downsizing the entire control lever without increasing rigidity of the entire control lever.
In second aspect of the invention, in addition to the effect of the invention as set forth in the first aspect of the invention, the second detent mechanism includes the detent body and the detent spring supported on the control lever, and the detent groove formed on the control rod, and is able to provide detention against the rotational operation reliably by resilient contact of the detent body urged by the detent spring with the detent groove on the control rod on the occasion of rotating the other one of the first and second rotary knobs.
Since the control rod also includes the engaging section that enables the electrical operational instructions, and the notched section that enables insertion of the lever shaft along the axial center of the lever guide hole in addition to the detent groove, the lever shaft can easily be inserted and assembled along the axial center of the lever guide hole on the occasion of assembly.
In this case, by rotating the control rod in one direction about the axis, the notched side of the control rod may be engaged with the locking section provided on the proximal side of the control lever by an urging force of the detent spring. Therefore, in this state of engagement, the lever shaft and the control rod do not project and drop out from the lever guide hole due to an urging force of the detent spring even when the operator unlinks hands, and thus assembly may be performed quite easily.
In the third aspect of the invention, in addition to the effect of the invention as set forth in the first or second aspect of the invention, when the other one of the first and second rotary knobs is rotated, the rotation can be constrained by abutment of the notched side of the control rod to the stopper provided on the proximal side of the lever guide at the limit of rotation, and thus the rotational operation of the other one of the first and second rotary knobs may be reliably performed.
In this case, since the first and second detent mechanisms do not work together in the direction of rotation, even when the other one of the first and second rotary knobs rotates and displaces over the limit due to the axial deflection caused by abutment of the notched side of the control rod to the stopper, one of the first and second rotary knobs does not rotate together, and thus malfunction can reliably be prevented.
In the fourth aspect of the invention, in addition to the effect of the invention as set forth in the second or third aspect of the invention, since the mounting space in communication with the lever guide hole is provided on the proximal side of the lever guide, the control rod may be disposed in the mounting space. Since the locking hole is formed on one side of the mounting space intersecting the axial center of the lever guide hole, the notched side of the control rod may be engaged with the locking hole via an urging force of the detent spring of the second detent mechanism by rotating the control rod in one direction about the axis, thereby reliably preventing dropping out of the lever shaft and the control rod when assembling.
Since the aforementioned locking hole is provided with the stopper, when the control rod is rotated to the limit, the notched side of the control rod can reliably be abutted to the stopper, and thus the other one of the first and second rotary knobs may reliably be positioned at the limit of rotation, thereby enabling precise operation.
In the fifth aspect of the invention, in addition to the effect of the invention as set forth in any one of the first to fourth aspects of the invention, since the first rotary knob and second rotary knob are disposed on the distal side of the control lever with the immovably mounted fixed knob interposed therebetween and thus the detent body provided on one of the first and second rotary knobs or on the fixed knob is brought into resilient contact with the detent groove formed on the other one of those by an urging force of the detent spring when rotating one of the first and second rotary knobs, detention against the rotational operation of the first and second rotary knobs may reliably be provided.